Central vacuum cleaner control system

ABSTRACT

A secondary, smaller vacuum pump is connected to the system&#39;&#39;s dust collecting tank to maintain a predetermined, minimum vacuum in the tank when the primary vacuum pump is not in use. When one of the covers sealing the system&#39;&#39;s several outlets is removed to insert a cleaning attachment, the sudden rush of atmospheric pressure into the tank momentarily closes a first pressure switch, which actuates the primary pump. The primary pump motor is kept energized through a holding circuit including a normallyclosed pressure switch, which finally opens and deenergizes the motor for the primary pump, when the system pressure has been lowered to a predetermined minimum value. The secondary pump, nevertheless, continues to run.

United States Patent [15] 3,669,145 [45 1 June 13, 1972 Primary Examiner-William R. Cline Attorney-Shlesinger, Fitzsimmons and Shlesinger ABSTRACT A secondary, smaller vacuum pump is connected to the system's dust collecting tank to maintain a predetermined, minimum vacuum in the tank when the primary vacuum pump is not in use. When one of the covers sealing the systems several outlets is removed to insert a cleaning attachment, the sudden rush of atmospheric pressure into the tank momentarily closes a first pressure switch,'which actuates the primary pump. The primary pump motor is kept energized through a holding circuit including a normally-closed pressure switch, which finally opens and deenergizes the motor for the primary pump, when the system pressure has been lowered to a predetermined minimum value. The secondary pump, nevertheless, continues to run,

6 Claims, 2 Drawing figures Holstrom [54] CENTRAL VACUUM CLEANER CONTROL SYSTEM [72] lnventor: Allan Holstrom, Rochester, N.Y. [73] Assignee: Fasco Industries, Inc., Rochester, NY. [57] [22] Filed: June 22, 1970 211 App]. No.: 47,994

52 user ..137/567, 15/319 [51] Int. Cl. ..A47l 5/38 [58] Field of Search ..l37/567; 15/314, 319

[56] 1 1 References Cited UNITED STATES PATENTS 1,618,667 2/1927 Melcher ..15/314 X 3,173,164 3/1965 Congdon ..15/314 3,283,093 11/1966 Bishop ..15/319 X 3,069,068 12/1962 Hansen ..15/319 X 1 IO f P'A'TENTEDJuu 13 m2 FIG. 1

OFF

2 INVENTOR.

ALLAN HOLSTROM ATTORNEYS CENTRAL VACUUM CLEANER CONTROL SYSTEM This invention relates to central vacuum cleaner systems, and more particularly to novel means for starting and stopping the central vacuum pump, which develops the vacuum in such a system.

Although in the past central vacuum cleaner systems have been used primarily in large office buildings, schools, theatres, and the like, it is becoming more and more common for the average home owner to incorporate such a system in his home, particularly in newly built homes. A typical such system comprises a vacuum pump, which is installed in the basement or utility room of the home, a manifold at the input side of the pump, and a plurality of air-tight pipes or outlets, which lead from the manifold to each of the rooms in the house. In each room the inlet to the vacuum pipe is covered by a springloaded-closed gasketed cover, which normally seals the pipe opening, but which can be opened to permit the connection to the system of a conventional cleaning hose attachment.

Heretofore the most common method employed for starting and stopping the vacuum pump in a system of the type described, has been to employ manually-operated electric switches, located at the outlets, and wired to the central pump. More recently, in order to eliminate the need for using electrical wiring to connect such control switches to the pump, a sonic hand transmitter has been used to send signals to the control unit for the system pump in order to eliminate the electrical wiring. This is not only a rather expensive solution for the elimination of the electrical wiring, but also presents the average housewife with the additional problems of keeping the transmitter out of the hands of children, and otherwise caring for the transmitter so that it will not become lost, misplaced or damaged.

It is an object of this invention to provide improved means for controlling the operation of the vacuum pump in a central vacuum cleaner system of the type described.

A more specific object of this invention is to provide for a system of the type described a control device, which is operative, upon connection of a cleaning tool into one of the system outlets, automatically to actuate the system vacuum pump.

A still further object of this invention is to provide a novel control device of the type described, which will eliminate much of the electrical wiring and/or hand operated switching devices heretofore utilized for controlling central vacuum cleaner systems.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawing.

In the drawing:

FIG. 1 is a schematic view illustrating fragmentarily and partially in section a central vacuum cleaner system incorporating a system control device made in accordance with one embodiment of this invention; and

FIG. 2 is a wiring-diagram illustrating one manner in which this control device can be wired for operation.

Referring now to the drawing by numerals of reference, and first to FIG. 1, l denotes a typical central vacuum cleaner tank containing a dust bag 12, which is interposed between the tank inlet and outlet ducts l3 and 14, respectively. The outlet duct 14 is connected in the usual manner to the input or intake of a conventional motor-driven vacuum pump 16. A check valve 18 in the output duct of pump 16 permits one-way flow of exhaust air from the pump.

A plurality of air-tight vacuum pipes or feeders 20 are connected at one end to the vacuum tank inlet or manifold 13, and have their outlet ends 22 opening on the walls or baseboards in different rooms, respectively, of the house or building in which the system is installed. Each outlet end 22 normally is sealed or closed by a gasketed, spring-loaded cover 24, which, typically, can be pivoted manually to open position to permit the connection of a tubular vacuum cleaner attachment in air-tight manner to the associated outlet 22.

As thus far described, the system is typical of those prior systems in which the system vacuum pump has been controlled, for example, by the above-noted sonic hand transmitter, or by the manually-operable switches, which are located in one or more of the rooms serviced by the system.

For controlling the primary pump 16 in the instant invention, a secondary, or low-pressure, motor driven vacuum pump 26 has its input or intake side connected, in the embodiment illustrated, by a duct 28 to the interior of tank 10 at the same side of the dust bag 12 as the intake duct 14 for the pump 16. Mounted in the duct 28 is a conventional check valve 30, which permits one-way flow of air from the tank 10. Mounted in the outlet of the pump 26 is a low-pressure air controlled or air vane switch 32 (FIGS. 1 and 2) having a normally-open switch contact 33, which is adapted to be closed when, during operation of the pump 26, one of the outlet covers 24 is opened to admit atmospheric pressure to the system as described hereinafter.

Referring to FIG. 2, 40 denotes a conventional, manuallyoperable, ON-OF F switch, which is movable to its ON position to apply power to the system through line 35 from lines L1 and L2 that are connected to a conventional alternating current (AC) power supply. Line 35 is connectable selectively through a single pole, double throw switch 42 either to a line 43 to effect automatic operation of the system controls, or to a line 44' to effect manual operation of the controls. The motor 27, which drives the low pressure pump 26, is connected directly between the lines 43 and 47, so that whenever power is applied to line 43 (i.e., automatic mode of operation) the motor 27 will be energized to operate the secondary pump 26.

Connected in parallel with the motor 27, and in series with one another between the lines 43 and 47 are the normallyopen pressure switch32, the operating coil 44 of a conventional relay 50, and a normally-closed diaphragm-type vacuum pressure switch 46, which is connected to tank 10 (FIG. 1) to be opened when the pump 16 has developed a maximum, predetermined vacuum in the tank. The relay 45 operates two normally-open switches 48 and 49, each of which is closed when the relay coil 44 is energized.

When switch 48 is closed it connects line 43 to a line 45, whichis connected through the motor 17, which drives the primary vacuum pump, to the line 47. Switch 49 is a holding switch, which, when closed, connects line 45 through the switch 49, the coil 44 and the switch 46 to the line 47 in parallel with the motor 17. Consequently, when the coil 44 is energized, switches 49 and 48 function to keep the motor 17 energized until switch 46 opens, as described in more detail hereinafter.

For use, switch 40 is first moved to its ON position. If switch 42 is then moved to automatic position, motor 27 is energized. This drive pump 26 to create a low vacuum pressure in tank 10 and in the ducts l3 and 20 of the system. At this time, check valve 30 is open and air is blocked from entering the system because valve 18 and covers 24 are closed. Also, switch 33 is open since no air is flowing through the system.

When one of the covers or receptacles 24 is opened, atmospheric air rushes into the system and, through the pump 26, closes the pressure switch 33. This energizes the relay coil 44 through switch 46, and thereby closes switches 47 and 48, which locks in the relay coil and turns on the vacuum cleaner motor 17. The pump 16 is thus driven to develop the high vacuum in tank 10 required to draw dust to the tank 10 through the particular inlet 22, in which the vacuum attachment (not illustrated) has been inserted. Check valve 30 is held closed by air pressure; and valve 18 is held open by exhaust air.

As long as the vacuum attachment is being used, the flow of air and dust into the tank 10 maintains the vacuum therein at a value beneath that for which the switch 46 is set to open. However, once the vacuum attachment is disconnected from the receptacle 22 to which it was attached, the associated cover 24 closes, Motor 17 will continue in operation, however, until the entire system is under high enough vacuum to open switch 7 46. The vacuum in the tank 10 will have closed the check valve 30, so that even through pump 26 is operating, the

switch contact 33 is in its open position. During this period the pump 17 will suck any dust in the system out of the duct 13 and feeders 20 so that the system is in effect self-cleaning, an additional advantage over conventional switch operated systems where the vacuum is shut off as soon as the control switch is moved to OFF position.

As soon as switch 46 opens, relay coil 44 is deenergized, thereby causing the switches 47 and 48 to return to their normally-open positions, shutting off motor 17.

Motor 17 then remains deenergized until the next time one of the covers 24 is opened. At such time air at atmospheric pressure will rush into the system, once again momentarily closing switch 33 to actuate the primary pump 16 in the manner described above. If, however, a prolonged period of time lapses before the system is again used for vacuum cleaning purposes, slight, unavoidable leakages in the system may cause a slight reduction in the vacuum in tank 10, and may thereby permit switch 46 to reclose before one of the covers 24 is again opened. This reclosing switch 46, however, will have no immediate efiect upon the system, because a slight leakage will not be sufiicient to cause contact 33 to close. Moreover, since the motor 27 is energized as long as the switch 40 is in its ON position and the switch 42 is in its Automatic position, the vacuum in tank 10, regardless of leakages in the system, will not fall below a predetermined value, due to the constant operation of the secondary pump 26. Thus, when switch 40 is in its ON position, and switch 42 is in the position illustrated in FIG. 2, the primary pump 16 will always be actuated upon opening one of the covers 24.

If switch 42 is swung to its Manual position to connect lines 43 and 44, the secondary pump 26 will not operate, nor will the switches 33 and 46 have any effect upon the system. Instead, the motor 17 will then be controlled directly through the ON-OFF switch 40.

While the secondary pump 26 and check valve 30 have been shown as connected to the tank at the same side of container 12 as the primary pump 16, these locations are not obligatory. The secondary pump and the check valve 30 can be connected to the tank below dust bag 12 or even to duct 13. All that is required is that they be in a position to be operated by in-rush of air upon opening of a wall receptacle. Switch 46 likewise may be located at either side of bag 12 or in duct 13.

From the foregoing it will be apparent that, assuming that the switch 40 is maintained in its ON position, the only manual operation involved in actuating the system pump 16 is the opening of one of the covers 24. This operation would have to be performed anyway in order to insert a vacuum attachment in one of the outlets 22. The instant invention provides an improved central vacuum cleaner system having a built-in control device for automatically actuating the system vacuum pump whenever a vacuum attachment is inserted into one of the system outlets. This eliminates the heretofore required step of first closing an electric switch or of operating a hand transmitter, before (or after) inserting a vacuum attachment into one of the system outlets.

Having thus described my invention, what I claim is:

1. A central vacuum cleaner system, comprising a sealed tank containing a dust container,

a plurality of air-tight ducts operatively connected at one end to said tank at one side of said container, said ducts being arranged to open at their opposite ends on different rooms in a building serviced by said system,

removable covers normally closed over and sealing said opposite ends of said ducts,

a primary vacuum pump having its intake connected to said tank at the opposite side of said container from said ducts, and operable to develop a primary vacuum in said container and tank, and

pressure-responsive switch means connected to said tank and operative, only when the pressure in said container and tank is below atmospheric pressure, automatically to actuate said primary vacuum pump upon opening of any of said covers.

2. A central vacuum cleaner system as defined in claim 1,

wherein said pressure-responsive switch means comprises a normally-open switch positioned in said system to be closed by the air that enters said container and tank through one of said ducts upon the opening of its associated cover, and

means is provided for automatically deactuating said pump, when the pressure in said container and tank reaches a predetermined value below atmospheric pressure.

3. A central vacuum cleaner system comprising a sealed tank containing a dust container,

a plurality of air-tight ducts operatively connected at one end to said tank at one side of said container, said ducts being arranged to open at their opposite ends on different rooms in a building serviced by said system,

removable covers normally closed over and sealing said opposite ends of said ducts,

a primary vacuum pump having its intake connected to said tank at the opposite side of said container from said ducts, and operable to develop a primary vacuum in said container and tank, and

means operative automatically to actuate said primary vacuum pump upon opening of any of said covers,

said means comprising a secondary vacuum pump having its intake connected to said tank and operable independently of said primary pump, to maintain the pressure in said tank at a minimal value below atmospheric pressure, when said covers are in their closed positions, and

pressure responsive means operative to actuate said primary pump, when the pressure in said tank increases in response to opening of one of said covers.

4. A central vacuum cleaner system as defined in claim 3,

including a first electric motor for operating said primary pump,

a second electric motor for operating said secondary pump,

and

means for connecting said second motor to a power supply to maintain said second motor energized independently of said first motor,

said pressure responsive means comprising a normally-open switch interposed between said first motor and said power supply, and operative in response to said increase in pressure in said tank to energize said first motor when one of said covers is opened.

5. A central vacuum cleaner system as defined in claim 4 including means for holding said first motor energized, after each closure of said normally-open switch, until the pressure in said tank reaches a maximum value below atmospheric, and

a second, normally closed, pressure responsive switch connected in circuit with said first motor and operative, when the pressure in said tank has dropped to a predetermined value, to deenergize said first motor and stop said primary pump.

6. A central vacuum cleaner system as defined in claim 5,

wherein said normally-open switch is mounted in the outlet of said secondary pump at the exterior of said tank, and

a check valve is interposed between said tank and said secondary pump operatively to block said tank and said primary pump from the inlet to said secondary pump, when said primary pump is operating. 

1. A central vacuum cleaner system, comprising a sealed tank containing a dust container, a plurality of air-tight ducts operatively connected at one end to said tank at one side of said container, said ducts being arranged to open at their opposite ends on different rooms in a building serviced by said system, removable covers normally closed over and sealing said opposite ends of said ducts, a primary vacuum pump having its intake connected to said tank at the opposite side of said container from said ducts, and operable to develop a primary vacuum in said container and tank, and pressure-responsive switch means connected to said tank and operative, only when the pressure in said container and tank is below atmospheric pressure, automatically to actuate said primary vacuum pump upon opening of any of said covers.
 2. A central vacuum cleaner system as defined in claim 1, wherein said pressure-responsive switch means comprises a normally-open switch positioned in said system to be closed by the air that enters said container and tank through one of said ducts upon the opening of its associated cover, and means is provided for automatically deactuating said pump, when the pressure in said container and tank reaches a predetermined value below atmospheric pressure.
 3. A central vacuum cleaner system comprising a sealed tank containing a dust container, a plurality of air-tight ducts operatively connected at one end to said tank at one side of said container, said ducts being arranged to open at their opposite ends on different rooms in a building serviced by said system, removable covers normally closed over and sealing said opposite ends of said ducts, a primary vacuum pump having its intake connected to said tank at the opposite side of said container from said ducts, and operable to develop a primary vacuum in said container and tank, and means operative automatically to actuate said primary vacuum pump upon opening of any of said covers, said means comprising a secondary vacuum pump having its intake connected to said tank and operable independently of said primary pump, to maintain the pressure in said tank at a minimal value below atmospheric pressure, when said covers are in their closed positions, and pressure responsive means operative to actuate said primary pump, when the pressure in said tank increases in response to opening of one of said covers.
 4. A central vacuum cleaner system as defined in claim 3, including a first electric motor for operating said primary pump, a second electric motor for operating said secondary pump, and means for connecting said second motor to a power supply to maintain said second motor energized independently of said first motor, said pressure responsive means comprising a normally-open switch interposed between said first motor and said power supply, and operative in response to said increase in pressure in said tank to energize said first motor when one of said covers is opened.
 5. A central vacuum cleaner system as defined in claim 4 including means for holding said first motor energized, after each closure of said normally-open switch, until the pressure in said tank reaches a maximum value below atmospheric, and a second, normally closed, pressure responsive switch connected in circuit with said first motor and operative, when the pressure in said tank has dropped to a predetermined value, to deenergize said first motor and stop said primary pump.
 6. A central vacuum cleaner system as defined in claim 5, wherein said normally-open switch is mounted in the outlet of said secondary pump at the exterior of said tank, and a check valve is interposed between said tank and said secondary pump operatively to block said tank and said primary pump from the inlet to said secondary pump, when said primary pump is operating. 